Extraction of residuum



Aug. 23, 1960 J. E. LAWSON, JR 2,950,244

EXTRACTION 0F RESIDUUM Filed Sept. 22, 1958 4| DEASPHALTED OIL WASH ML 1 METAL emnmss cauo: PETROLEUH ,sxnucnou Rsswuuu, zone a I;

1 :/-LIGHT PHASE ,HEAVY muss 35 m muvv muss 23 \l /L|GHT PHASE 37 HEAVY PHASE JET ,-JSEAL PAN INCORPORATOR 25 7 l2 LIGHT mus:

LIGHT HYDROCARBON SOLVENT INVENTOR.

ASPHALT SOLUTION ilnite States Patent 2,950,244 Patented Aug. 23, 1960 EXTRACTIUN OF RESIDUUM .lohn E. Lawson, in, Baytown, Tex., assignor, by mesne assignments, to Esso Research and Engineering (Zornpany, Elizabeth, NJ, a corporation of Delaware Filed Sept. 22, 1958, 'Ser. No. 762,301

8 Claims. or. 203-4429 The present invention is directed to the extraction of crude petroleum residuum. More particularly, the invention is concerned with the extraction of crude petroleum residuum employing a liquefied, normally gaseous, hydrocarbon solvent. In its more specific aspects, the invention is directed to recovering increased yields of deasphalted oil from crude petroleum residuum by extraction of the crude petroleum residuum with a liquefied, normally gaseous hydrocarbon solvent.

The present invention may be briefly described as the extraction of a crude petroleum residuum which contains asphalt constituents and oil with a liquefied, normally gaseous hydrocarbon solvent in which a solution of the residuum in the solvent is introduced into an elongated, vertical extraction zone at an upper level thereof. The solvent is introduced into the extraction zone at a lower level thereof and the solvent and solution are maintained in said zone under extraction conditions of temperature and pressure. The solvent and solution are flowed counter-currently in said zone and at least a light phase and at least a heavy phase are formed in said zone between the upper level and the lower level. The light phase which comprises solvent and oil is dispersed in the heavy phase which comprises asphalt and solvent. Thereafter there are recovered from said zone asphalt-free oil and an asphalt constituent phase.

The liquefied, normally gaseous hydrocarbon solvent may be propane and/or butane with small amounts of heavier and lighter constituents. The liquefied, normally gaseous hydrocarbon may also include propylene and the butylenes. A satisfactory solvent may comprise about 66 percent of C hydrocarbons and a small amount of lighter materials and about 34 percent of C hydrocarbons, including a small amount of heavier materials. The solvent may satisfactorily be either propane and the butanes or may contain propylene and propane and the butylenes and butanes. The amount of material lighter than the C hydrocarbons may be of the order of about 1.5 percent by volume while the amount of heavier material than the C, hydrocarbons may be no greater than about 1 percent by volume. Satisfactory operations are obtained with a mixture comprising about 60-63 percent propane and/or propylene and about 29-32 percent of butanes and/or butylenes with the remainder being some lighter and heavier material.

The extraction temperatures may range from about 100 to about'250 F. while pressures will be suflicient to maintain a liquid phase. In other words, a pressure may be employed in excess of the vapor pressure of the solvent at the operating temperature.

The light phase of the present invention is predominantly solvent and oil and may have a density of about 0.4 to about 0.6 while the heavy phase is predominantly asphalt constituents and solvent and may have a density from about 0.7 to 0.9.

In the practice of the present invention, the residuum may be diluted with about .2 to about .5 volume f solvent per volume of residuum to form the solution which is introduced into the extraction zone.

The amount of liquefied, normally gaseous hydrocr-bon solvent may suitably be in the range from about three volumes to about ten volumes per volume of residuum.

The ratio of light phase to heavy phase may be in the range from about 3 to 30 to 1 with satisfactory results being obtained at a ratio of light phase to heavy phase of about 7 to 1.

It is contemplated that, in the practice of the present invention, a heavy wash oil may be introduced into the extraction zone at a point above the point where the residuum solution is introduced and the wash oil may also be introduced along with the hydrocarbon solvent. The amount of solvent-free wash oil introduced into the extraction zone may be in the range from about 0.05 to 0.20 volume per volume of crude petroleum residuum. A suitable wash oil may be obtained from crude petroleurn from the Hawkins Field in Texas or may be a. catalytic tar or a heavy fraction such as described in US. Patents 2,793,168 and 2,777,802. Other wash oils suitable in the practice of the present invention are described in Serial No. 493,371, filed March 10, 1955, now US. Pat. No. 2,853,426, for Nick P. Peet.

The present invention will be further illustrated by reference to the drawing in which the sole figure is an elevational view in section of an extraction zone for practice of a preferred mode.

Referring now to the drawing, numeral 11 designates a charge line by way of which a light hydrocarbon solvent comprising a major amount of propane and a minor amount of butanes is introduced into the system from a source not shown. Line 11 leads into a jet incorporator 12 and from thence into a vertical, elongated extraction zone 13. Vertical elongated extraction Zone 13 is provided with a steam coil 14 in its upper end, into which steam is introduced by way of line 15, controlled by valve i6, and this exhaust steam is discharged by way of line 17. A plurality of steam coils may be used as may be required.

Vertical elongated extraction zone 13 may be provided with a plurality of vertically spaced apart expanded metal gratings 18 and is also provided with perforated trays 19, 20, 21, 22, 23, and 24, as well as with a seal pan 25. The trays i9, 253, 21, 22, 23, and 24 are vertically spaced apart and are provided with vertical members 26, 2.7, 28, 29, 30, and 31 as illustrated which form a plurality of weirs; plate 19 is provided with a Weir 32 to isolate a portion of the plate 19 for introduction of the solution as will be described. The vertical member 31 forms a seal with the seal pan 25 as has been illustrated.

The plates 26, 27, 23, 29, 30, and 31 are arranged to provide flow as will be described.

The plates ltd-224 inclusive are perforated for upward flow through the plates in a manner which will be described.

Extraction zone 13 is also provided with a line 10 which leads into a spray 33 by way of which a heavy wash oil is introduced into the system. Line 10 connects with line 11 by way of branch line 34- to allow wash oil to be introduced with the solvent through line 11. Flow ratio through line 10 and 35 are controlled by Valves 35a and 34" respectively.

Crude petroleum residuum is introduced into the system through line 36 and has admixed with it solvent introduced from line H from branch line 37 controlled by valve 38, line 36 being controlled by valve 39 and introducing the solution of crude petroleum residuum into the extraction zone onto plate 19 as shown.

Line 11 which contains jet 12 introduces solution into zone 13 below a suitable splash plate 40 as shown in the drawing.

Deasphalted oil in solution in the solvent is withdrawn from zone 13 by way of line 41 and may be further treated for removal of metal contaminants as described in U.S. Patent 2,793,168 and removal of solvent by a suitable means. Asphalt is discharged in solution by way of line 42 Controlled by valve 42:: for further treatment for recovery of solvent.

A branch line 43 controlled by valve 44 is provided for introducing as may be desired a portion of the asphalt solution withdrawn by line 42 into jet 12 for recycling to zone 13 with the solvent introduced by line 11.

By virtue of the arrangement of plates 1924 inclusive and th e vertical members 26-31 inclusive and by virtue of the flow through the extraction zone 13, there is formed on the several plates a plurality of heavy phases 45, 46, 47, 48, 49, and 50, and a plurality of light phases 51, 52, 53, 54, 55, and 55avvith the light phases 51-55a inclusive being introduced into an adjacent heavy phase through the perforations 56, 57, 58, 59, 60, and 61 in plates 19, 20, 21, 2.2, 23, and 24, respectively, as illustrated. By virtue of dispersing a light phase into an adjacent heavy phase in the practice of the present invention, it is possible to increase the yields of deasphalted oil in a substantial and unexpected manner. This comparison is drawn with normal practice wherein heavy phase dispersed in the light phase comprises the flow regime. Dispersion of the light phase, which may be four to twenty times greater in volume, into the heavy phase causes a greater interfacial area to be created, thus giving rise to a greater opportunity for mass transfer which results in higher contacting efiiciency. The light phase has a much lower viscosity and therefore greater mobility than the heavy phase. This factor gives rise to greater circulation within droplets of the light phase as compared to heavy phase droplets which results in higher mass transfer coeflicients, also increasing efiiciency of contacting. This results in improved extraction efficiency and 4 considerable operational advantages in deasphalting operations. For example, control of phase interface on each tray is positive. Also contacting intensity may be controlled to any desired level by varying design features of 5 the perforated trays and improved yields of deasphalted oil are obtained. Additionally, an asphalt of a greater specific gravity is obtained over that normally obtainable by Virtue of recovering increased yields of deasphalted oil.

In order to illustrate the invention further, comparative extractions were made on a crude petroleum residuum operating conditions and yields with the first column showing the invention and second column theconventional operation.

TABLE I Barrels per day Charge, b./d. (Corrected to 60 F.) 11, 800 11, 760 Solvent Circulation, b./d.'

To Tower 46, 600 46, 500 Predjlufinn 4, 290 5, 300 Deasphalted Oil, b./d 6, 060 4, 350 Wash Oil Rate, b./d 660 660 Yield, Volume Percent 53.6 37. 0 Tower Temperatures, F.:

Top 175 174 Bottom 170 170 Flux to Asphalt, b./d 1, 550 1, 500 Fluxed Asphalt, b. d 7, 450 9, 570 Solvent/Residuum, Ratio, Total 4. 5 4. 41

From the foregoing Table I, it will be seen from the TABLE II 1 2 Residuum Charge Deas- Fluxed Deas- Fluxed phgllii'ed Asphalt Asphalt Flux Wash Oil phgliiied Asphalt Asphalt Flux Wash Oil Specific Gravity 1 0.9910 0.9441 1.0383 1.0430 0. 9463 1.0175 1.0212 APLI 11. 5 18. 7 4. 5 10. 3 36. 1 5. 6 18. 7. 12. 0 34.0 8. 5 Conradson Carbon 14. 23 3. 67 23.7 13.0 3.87 18.4 9- ulfur, Wt. Percent L... 2.40 1. 33 3. 11 3. 52 0.287 1.45 1.28 2. 69 2.34 3. 39 1. 33 Aniline Point 222 2.21 0. 134 0. 12

217 103. 2 197. 5 79.1 275 75. 3 176. 7 SSF at210 F 99. 6 15. 5 65. 1 SSF 370 131. 3 Agg. Ash 1 0.0277 0.00192 0.0185 0.00259 Water Sol. Ash 0.03 0.002 0.011 Flash, PM 188 176 215 Explosivity, Percent- 35.0 18.0 8 7 0 10.0

7 Mi 95.5% 011 390 48% off at 1,132 at 1,132 at 1,132 at 1,132

1 Average of at least two determinations.

cal as close as could be obtained in a commercial operation.

Further to show the improvement of the present invention, the following inspection characteristics are shown in Table II wherein the data under 1 shows the present invention; wherein the data under 2 shows the comparative operation not utilizing the present invention. Characteristics of the flux and wash oil are also shown. Also, the fluxed asphalt characteristics from the two operations are also presented.

It may be seen from the inspection in Table II that the deasphalted oil from the two operations were substantially identical in quality but yet increased yields of deasphalted oil were obtained in accordance with the present invention, which shows that at a constant yield, improved quality deasphalted oil with a lowered metal content is obtainable. This is quite important and useful in preparing feeds for cracking operations, and the like.

It is noted that the asphalt obtained in the present invention is considerably heavier than the asphalt from the comparative run, showing that greater quantities of the deasphalted oil have been recovered.

ttention is especially directed to the lowered Conradson carbon of the deasphalted oil in the practice of the present invention over that obtained in the comparative operation.

From the foregoing runs, it may be concluded that the present invention allows obtaining of substantially improved results in that greater yields of deasphalted oil are obtainable than was possible heretofore without a sacrifice in quality. In other words, it is now possible to recover deasphalted oil in substantially improved yields for use as a catalytic cracking feedstock as may be desired.

The nature and objects of the present invention having been completely described and illustrated, what I wish to claim as new and useful and secure by Letters Patent is:

l. A method for extracting a residuum fraction to obtain a substantially asphalt-free oil which comprises form ing a solution of a crude petroleum residuum containing asphalt constituents and oil in a liquefied normally gaseous hydrocarbon solvent, introducing said solution into an elongated vertical extraction zone at an upper level thereof, introducing said solvent into said zone at a lower level thereof, said solution and solvent being maintained in said zone under extraction conditions including a temperature between 100 and 250 F. and pressure suficient to maintain a liquid phase, flowing countercurrently in said zone said solvent and solution, forming in said zone at least a light phase comprising predominantly said solvent and said oil, forming in said zone at least a heavy phase comprising predominantly said asphalt constituents and solvent, dispersing said light phase into said heavy phase, said light phase and heavy phase being in a ratio in the range from about 3 to 30:1, and said light phase having a density of about 0.4 to about 0.6 and said heavy phase having a density of about 0.7 to 0.9, and recovering from said zone increased yields of substantially asphalt-free oil and an asphalt constituent phase.

2. A method in accordance with claim 1 in which a heavy wash oil is introduced into said Zone above said solution.

3. A method in accordance with claim 1 in which the solvent comprises predominantly C and C hydrocarbons.

4. A method extracting a residuum fraction to obtain a substantially asphalt-free oil which comprises forming a solution of a crude petroleum residuum containing asphalt constituents and oil in a liquefied normally gaseous hydrocarbon solvent having from 3 to 4 carbon atoms in the molecule, introducing said solution into an elongated vertical extraction zone at an upper level thereof, introducing said solvent into said zone at a lower level thereof, said solution and solvent being maintained in said zone under extraction conditions including a temperature in the range between and 250 F. and pressure sufilcient to maintain a liquid phase, flowing countercurrently in said zone said solvent and solution, forming in said zone at least a light phase comprising predominantly said solvent and said oil, forming in said zone at least a heavy phase comprising predominantly asphalt constituents and solvent, said light and heavy phases being formed between said upper level and said lower level in said zone, dispersing said light phase into said heavy phase, said light phase and heavy phase being in a ratio in the range from about 3 to 30:1, and said light phase having a density of about 0.4 to about 0.6 and said heavy phase having a density of about 0.7 to 0.9, and recovering from said zone increased yields of substantially asphalt-free oil and an asphalt constituent phase.

5. A method in accordance with claim 4 in which a portion of the asphalt constituent phase is recycled to said zone in admixture with said solvent.

6. A method in accordance with claim 4 in which a heavy wash oil is introduced into said zone above said solution.

7. A method for extracting a residuum fraction to obtain a substantially asphalt-free oil which comprises forming a solution of a crude petroleum residuum containing asphalt constituents and oil in a liquefied normally gaseous hydrocarbon solvent, introducing said solution into an elongated vertical extraction zone at an upper level thereof, introducing said solvent into said zone at a lower level thereof, said solution and solvent being maintained in said zone under extraction conditions including a temperature between 100 and 250 F. and

pressure sufficient to maintain a liquid phase, flowing countercurrently in said zone said solvent and solution, forming in said zone a plurality of light phases comprising predominantly said solvent and said oil, forming in said zone a plurality of heavy phases comprising predominantly asphalt constituents and solvent, said light and heavy phases being formed between said upper level and said lower level in said zone with a light phase adjacent a heavy phase, dispersing each light phase into its adjacent heavy phase, said light phases and said heavy phases being in a ratio in the range from about 3 to 30:1, and said light phase having a density of about 0.4 to about 0.6 and said heavy phase having a density of about 0.7 to 0.9, and recovering from said zone increased yields of substantially asphalt-free oil and an asphalt constituent phase.

8. A method for extracting a residuum fraction to obtain a substantially asphalt-free oil which comprises forming a solution of a crude petroleum residuum containing asphalt constituents and oil in a liquefied normally gaseous hydrocarbon solvent having from 3 to 4 carbon atoms in the molecule introducing said solution into an elongated vertical extraction zone at an upper level thereof, introducing said solvent into said zone at a lower level thereof, introducing a heavy wash oil into said zone at a point above the introduction of said solu tion, said solution and solvent being maintained in said zone under extraction conditions including a temperature between 100 and 250 F. and pressure sufficient to maintain a liquid phase, flowing countercurrently in said zone said solvent and solution, forming in said zone at least a light phase comprising predominantly said solvent and said oil, forming in said zone at least a heavy phase comprising predominantly asphalt constituents and solvent, said light and heavy phases being formed between said upper level and said lower level in said zone, dispersing said light phase into said heavy phase, said light phase and heavy phase being in a ratio in the range from about 3 to 30:1, and said light phase having a density of about 0.4 to about 0.6 and said heavy phase having adensity of abont 0.7 to.0.9, recovering. from said zone increased yields of substantially asphalt-free oil andian asphalt constituent phase, and recycling a portion of the asphalt constituent phase to said zone in admixture with said solvent.

References Cited in the file of this patent UNITED STATES PATENTS 2,213,798 Anne Sept. 3, 1940 -8 Clarke Dec. '24, 1940 Dickinson et a1. J an. 23, 1945 Davis L Oct.-12, 1948 Willauer Jan. 16, 1951 Brown et *al. June 26, 1956 Feet Sept. 23, 1958 

1. A METHOD FOR EXTRACTING A RESIDIUM FRACTION TO OBTAIN A SUBSTANTIALLY ASPHALT-FREE OIL WHICH COMPRISES FORMING A SOLUTION OF A CRUDE PETROLEUM RESIDUUM CONTAINING ASPHALT CONSTITUENTS AND OIL IN A LIQUIFIED NORMALLY GASEOUS HYDROCARBON SOLVENT, INTRODUCING SAID SOLUTION INTO AN ELONGATED VERTICAL EXTRACTION ZONE AT AN UPPER LEVEL THEREOF, INTRODUCING SAID SOLVENT INTO SAID ZONE AT A LOWER LEVEL THEREOF, SAID SOLUTION AND SOLVENT BEING MAINTAINED IN SAID ZONE UNDER EXTRACTION CONDITIONS INCLUDING A TEMPERATURE BETWEEN 100* AND 250*F. AND PRESSURE SUFFICIENT TO MAINTAIN A LIQUID PHASE, FLOWING CONTERCURRENTLY IN SAID ZONE SAID SOLVENT AND SOLUTION, FORMING IN SAID ZONE AT LEAST A LIGHT PHASE COMPRISING PREDOMINANTLY SAID SOLVENT AND SAID OIL, FORMING IN SAID ZONE AT LEAST A HEAVY PHASE COMPRISING PREDOMINANTLY SAID ASPHALT CONSTITUENTS AND SOLVENT, DISPERSING SAID LIGHT PHASE INTO SAID HEAVY PHASE, SAID LIGHT PHASE AND HEAVY PHASE BEING IN A RATIOK IN THE RANGE FROIM ABOUT 3 TO 30:1, AND SAID LIGHT PHASE HAVING A DENSITY OF ABOUT 0.4 TO ABOUT 0.6, AND SAID HEAVY PHASE HAVING A DENSITY OF ABOUT 0.7 TO 0.9, AND RECOVERING FROM SAID ZONE INCREASED YIELDS OF SUBSTANTIALLY ASPHALT-FREE OIL AND AN ASPHALT CONSTITUENT PHASE. 